customised user wizard including roles

Hi all

I've customised my 'create user wizard' to include select a role before the step is completed.

However it's possible to complete the steps without slecting a role. 

Can anyone see what I'm doing incorrectly here?  The required field val, doesn't appear to be working?

 1 <asp:WizardStep runat="server" ID="wsAssignUserToRoles" AllowReturn="False" Title="Step 2: Assign User To Roles"
2 OnActivate="AssignUserToRoles_Activate" OnDeactivate="AssignUserToRoles_Deactivate">
3 <table>
4 <tr>
5 ...